JP2005330943A - Control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a suitable cooperative control between a fuel injection device and a variable compression ratio mechanism in an internal combustion engine having the dual type fuel injection device and the variable compression ratio mechanism. <P>SOLUTION: This control device of the internal combustion engine comprises a fuel injection valve in an intake passage, a cylinder fuel injection valve, the variable compression ratio mechanism, and a control means performing the cooperative control of these devices. When the internal combustion engine is in a non-warmup state, a compression ratio becomes higher than that after warmup is completed and the fuel injection ratio of the fuel injection valve in the intake passage becomes higher than that of the cylinder fuel injection valve to increase heat efficiency, reduce exhaust emission, and promote warmup. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine including a fuel injection valve that injects fuel into a cylinder, a fuel injection valve that injects fuel into an intake passage, and a variable compression mechanism that changes a compression ratio.

  In recent years, an internal combustion engine equipped with a variable compression ratio mechanism that changes compression is known as an internal combustion engine mounted on a vehicle or the like for the purpose of reducing fuel consumption and improving efficiency (see, for example, Patent Document 1).

On the other hand, there is known an internal combustion engine including a dual-type fuel injection device having both an in-cylinder fuel injection valve for injecting fuel into a cylinder and a port fuel injection valve for injecting fuel into an intake port (for example, a patent) Reference 2).
JP 2003-206871 A JP 2002-48035 A

  By the way, there is no known technique for suitably controlling an internal combustion engine including both a variable compression ratio mechanism and a dual type fuel injection device.

  The present invention has been made in view of the above circumstances, and by providing a control technique suitable for an internal combustion engine equipped with a variable compression ratio mechanism and a dual type fuel injection device, it is possible to improve thermal efficiency and fuel consumption. The purpose is to plan.

  The present invention employs the following means in order to solve the above problems. That is, the present invention includes an in-cylinder fuel injection valve that injects fuel into the cylinder, an intake passage fuel injection valve that injects fuel into the intake passage, and a variable compression ratio mechanism that can change the compression ratio. In the internal combustion engine, by providing a control means for cooperatively controlling the in-cylinder fuel injection valve, the intake passage fuel injection valve, and the variable compression ratio mechanism based on a parameter relating to the operating state of the internal combustion engine, improvement in thermal efficiency and fuel consumption I tried to improve.

  For example, when the control means determines that the internal combustion engine is in a non-warm-up state based on the above-described parameters, the control means increases the compression ratio and increases the fuel injection ratio of the fuel injection valve in the intake passage. The mechanism, the cylinder fuel injection valve, and the intake passage fuel injection valve may be controlled.

  When the internal combustion engine is in a non-warm-up state, the temperature of the intake passage wall surface and combustion chamber wall surface is low, so the fuel injected from the intake passage fuel injection valve and the in-cylinder fuel injection valve is less likely to vaporize (atomize). Difficult to form a flammable mixture.

  In particular, when fuel is injected from the in-cylinder fuel injection valve, the fuel tends to be less atomized (vaporized) than when fuel is injected from the fuel injection valve in the intake passage. Further, when fuel is injected from the in-cylinder fuel injection valve, the in-cylinder temperature tends to decrease because the thermal energy in the cylinder is lost when the fuel is vaporized (atomized).

On the other hand, if the compression ratio is increased when the internal combustion engine is in a non-warm-up state and the fuel injection ratio of the fuel injection valve in the intake passage is higher than that in the cylinder fuel injection valve, the cylinder temperature is likely to increase and decrease. It becomes difficult to do. That is, when the compression ratio is increased, the compression end temperature in the cylinder rises, and the fuel injection ratio of the fuel injection valve in the intake passage is increased, thereby reducing the thermal energy in the cylinder that is consumed for fuel vaporization. As a result, the thermal efficiency of the internal combustion engine is improved and warm-up is promoted.

  After the warm-up of the internal combustion engine is completed, stratified combustion can be realized by increasing the fuel injection ratio of the in-cylinder fuel injection valve (preferably by injecting all of the target fuel injection amount from the in-cylinder fuel injection valve). If the warm-up of the internal combustion engine is promoted as described above, it is possible to switch to the stratified combustion operation at an early stage after the cold start, and it becomes possible to obtain the fuel efficiency improvement effect.

  The parameters related to the warm-up state of the internal combustion engine include the coolant temperature, the lubricating oil temperature, the elapsed time from the start (operation time), the integrated intake air amount from the start, and the integrated fuel injection amount from the start. Etc. can be illustrated.

  Next, when the control means determines that the internal combustion engine is in a high speed / high load operation state based on the above parameters, the control means increases the compression ratio and increases the fuel injection ratio of the in-cylinder fuel injection valve. The mechanism, the cylinder fuel injection valve, and the intake passage fuel injection valve may be controlled.

  When the internal combustion engine is in a high rotation / high load operation state, the time required for one cycle is shortened and the target fuel injection amount is increased, so that it is necessary to mix fuel and intake air in a short time. In addition, when fuel is injected from the in-cylinder fuel injection valve, the time that can be spent for mixing fuel and intake air is shorter than when fuel injection is performed from the fuel injection valve in the intake passage.

  When the internal combustion engine is in a high speed / high load operation state, the fuel injection ratio of the fuel injection valve in the intake passage is increased from the in-cylinder fuel injection valve to reduce the time spent for mixing the fuel and the intake air. A way to make it longer is conceivable.

  However, when the fuel injection ratio of the fuel injection valve in the intake passage becomes high, a large amount of fuel injected from the fuel injection valve in the intake passage obstructs the flow of intake air in the intake passage, thereby reducing the charging efficiency of the intake air. There is.

  On the other hand, when the internal combustion engine is in a high speed / high load operation state, if the fuel injection ratio of the in-cylinder fuel injection valve is higher than that in the intake passage fuel injection valve and the compression ratio is increased, the intake passage fuel injection valve Decreasing the amount of fuel injected (including the case where the fuel injection amount becomes zero) suppresses a decrease in charging efficiency of the intake air and promotes fuel vaporization (atomization) by increasing the in-cylinder temperature accompanying an increase in the compression ratio. Is done. As a result, the thermal efficiency is improved and the engine output is improved.

  If the compression ratio is increased when the internal combustion engine is in a high speed / high load operation state, knocking is likely to occur, but the in-cylinder temperature is lowered by the fuel injected from the in-cylinder fuel injection valve. Occurrence can be suppressed.

  Note that the target fuel injection amount increases and the in-cylinder temperature tends to decrease as the load of the internal combustion engine increases. Therefore, the compression ratio may increase as the load increases.

  Further, in addition to the high rotation / high load operation state of the internal combustion engine, the compression ratio is increased and the fuel injection ratio of the in-cylinder fuel injection valve is increased even when the internal combustion engine is in the low rotation / high load operation state. Good.

  This is a control suitable for an internal combustion engine combined with an automatic transmission capable of continuously changing a gear ratio. An internal combustion engine combined with an automatic transmission that can continuously change the gear ratio has many opportunities to be operated in a low-rotation / high-load operation region. Effective for improving fuel efficiency.

  Therefore, if the compression ratio is increased and the fuel injection ratio of the in-cylinder fuel injection valve is higher than that of the fuel injection valve in the intake passage when the internal combustion engine is in a low rotation / high load operation state, the thermal efficiency decreases due to the reduction of the compression ratio. Therefore, fuel consumption can be improved. Further, since the in-cylinder temperature is easily lowered by increasing the fuel injection ratio of the in-cylinder fuel injection valve, occurrence of knocking due to an increase in the compression ratio is suppressed.

  As a result, it is possible to increase the thermal efficiency while suppressing knocking in the low rotation / high load operation region, and to improve the fuel efficiency of the internal combustion engine.

  Examples of the parameters related to the engine speed of the internal combustion engine include a crankshaft rotation signal, a camshaft rotation signal, and a mechanical fuel injection pump rotation signal. Moreover, as a parameter regarding the load of an internal combustion engine, the operation amount (accelerator opening degree) of an accelerator pedal can be illustrated.

  Next, the present invention can also be suitably applied to an internal combustion engine provided with a variable valve mechanism that increases the kinetic energy of intake air by changing the valve opening characteristics of the intake valve at low load.

  For example, when the control means determines that the internal combustion engine is in a low-load operation state after completion of warm-up based on the above parameters, the compression ratio becomes low and the fuel injection ratio of the in-cylinder fuel injection valve becomes high. The variable compression ratio mechanism, the cylinder fuel injection valve, and the intake passage fuel injection valve may be controlled.

  Since the intake kinetic energy is converted into thermal energy in the cylinder, the in-cylinder temperature is likely to rise as the intake kinetic energy increases. For this reason, if the kinetic energy of the intake air increases when the internal combustion engine is in a low-load operation state before the warm-up is completed, fuel vaporization (atomization) is promoted due to an increase in the in-cylinder temperature and warm-up is also promoted. The

  On the other hand, if the variable valve mechanism operates to increase the kinetic energy of intake air when the internal combustion engine is in a low-load operation state after completion of warm-up, knocking may be induced due to the effect of increasing the in-cylinder temperature. In particular, since the conventional variable compression ratio mechanism operates to increase the compression ratio as the load decreases, knocking is likely to occur.

  Therefore, when the internal combustion engine is in a low load operation state after completion of warm-up and the variable valve mechanism operates to increase the kinetic energy of intake air, the internal combustion engine is in a non-warm-up state or the variable valve mechanism. The compression ratio is lowered and the fuel injection ratio of the in-cylinder fuel injection valve is increased as compared with the case where the engine does not operate to increase the kinetic energy of intake air (including the case where the variable valve mechanism is not provided). .

  In this case, the in-cylinder temperature decreases due to a synergistic effect between the reduction in the compression ratio and the increase in the fuel injection ratio of the in-cylinder fuel injection valve. As a result, the occurrence of knocking is suppressed. Further, when the reduction in the compression ratio and the increase in the fuel injection ratio of the in-cylinder fuel injection valve are used in combination, the amount of reduction in the compression ratio can be reduced compared to the case where knocking is suppressed only by the reduction in the compression ratio, and the thermal efficiency. Can be reduced.

In addition, since the in-cylinder temperature can be lowered to some extent by increasing the fuel injection ratio of the in-cylinder fuel injection valve, the fuel injection ratio of the in-cylinder fuel injection valve may be increased without reducing the compression ratio. . In this case, the occurrence of knocking can be suppressed while maintaining the effect of improving the thermal efficiency by the variable compression ratio mechanism.

  Next, the present invention can be suitably applied to an internal combustion engine including a supercharger for compressing intake air.

  For example, when the internal combustion engine provided with the supercharger is in a high load operation state, the control means includes a variable compression ratio mechanism, a cylinder so that the compression ratio decreases and the fuel injection ratio of the in-cylinder fuel injection valve increases. The internal fuel injection valve and the intake passage internal fuel injection valve may be controlled.

  When an internal combustion engine equipped with a supercharger is in a high-load operation state, the supercharging pressure rises and the in-cylinder pressure increases, so that knocking is likely to occur. In order to suppress the occurrence of such knocking only by compression ratio control, it is necessary to greatly reduce the compression ratio. However, if the compression ratio is significantly reduced, the thermal efficiency of the internal combustion engine is reduced and the fuel efficiency is deteriorated.

  Therefore, when the internal combustion engine equipped with the supercharger is in a high load operation state, if the fuel injection ratio of the in-cylinder fuel injection valve is increased in addition to the reduction in the compression ratio, the in-cylinder fuel injection valve Since the temperature in the cylinder is reduced to some extent by the injected fuel, knocking can be suppressed without significantly reducing the compression ratio. As a result, a decrease in the thermal efficiency of the internal combustion engine can be minimized, and deterioration in fuel consumption can also be suppressed.

  As a parameter for determining whether or not the internal combustion engine equipped with a supercharger is in a high load operation state, a supercharging pressure is used instead of the aforementioned operation amount (accelerator opening) of the accelerator pedal. Also good. That is, the control means may determine that the load on the internal combustion engine is higher as the boost pressure is higher, and may determine that the load on the internal combustion engine is lower as the boost pressure is lower.

  According to the present invention, since the variable compression ratio mechanism and the dual type fuel injection device can be suitably coordinated controlled according to the operating state of the internal combustion engine, fuel efficiency and thermal efficiency are further improved by the synergistic effect of both.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine according to the present invention. The internal combustion engine 1 shown in FIG. 1 is of a reciprocating type in which the compression ratio (compression ratio = (stroke volume + combustion chamber volume) / combustion chamber volume) is variable by increasing / decreasing the combustion chamber volume while keeping the stroke volume constant. It is an internal combustion engine.

  The internal combustion engine 1 includes a crankcase 3 in which a crankshaft 2 is rotatably mounted, a cylinder block 4 slidably attached to the crankcase 3 in the cylinder axial direction, and an upper portion of the cylinder block 4. A cylinder head 5 and an oil pan case 6 attached to the bottom of the crankcase 3 are provided.

  A cylinder 7 is formed in the cylinder block 4. A piston 8 is fitted to the cylinder 7 so as to be slidable in the cylinder axial direction. The piston 8 is connected to the crankshaft 2 via a connecting rod 9.

  The cylinder head 5 is provided with an intake port 11 and an exhaust port 12 that communicate with the combustion chamber 10. An intake pipe 13 that communicates with the intake port 11 and an exhaust pipe 14 that communicates with the exhaust port 12 are connected to the cylinder head 5.

  The cylinder head 5 is provided with an intake valve 15 for opening and closing the intake port 11, and the intake valve 15 is driven to open and close by an intake camshaft 16.

  The cylinder head 5 is provided with an exhaust valve 17 for opening and closing the exhaust port 12, and the exhaust valve 17 is driven to open and close by an exhaust camshaft 18.

  The cylinder head 5 is provided with an ignition plug (spark plug) 19 that generates a spark in the combustion chamber 10.

  A driving mechanism 20 that displaces the cylinder block 4 toward the top dead center side or the bottom dead center side in the cylinder axial direction is provided at the engaging portion between the cylinder block 4 and the crankcase 3. The drive mechanism 20 corresponds to the variable compression ratio mechanism according to the present invention, and for example, a mechanism disclosed in Japanese Patent Application Laid-Open No. 2003-206761 can be used.

  The internal combustion engine 1 according to the present embodiment has two fuel injection valves, an in-passage fuel injection valve 21 that injects fuel into the intake port 11 and an in-cylinder fuel injection valve 22 that injects fuel into the combustion chamber 10. A dual type fuel injection device.

  Further, a crank position sensor 23, a water temperature sensor 24, an accelerator position sensor 25, and an air flow meter 26 are attached to the internal combustion engine 1, and these are electrically connected to an ECU 27 (Electronic Control Unit).

  The ECU 27 is an arithmetic logic operation circuit including a CPU, a ROM, a RAM, a backup RAM, and the like. The ECU 27 determines the operating state of the internal combustion engine 1 using the output signals of the various sensors described above as parameters, and according to the determined operating state. Thus, the drive mechanism 20, the intake passage fuel injection valve 21, and the in-cylinder fuel injection valve 22 are cooperatively controlled.

  The cooperative control in the present embodiment is executed when the internal combustion engine 1 is in a cold state (non-warm-up state) before the warm-up is completed. Hereinafter, the cooperative control in the present embodiment will be described with reference to FIG.

  FIG. 2 is a flowchart showing a cold cooperative control routine. The cold cooperative control routine is a routine that the ECU 27 executes every predetermined time (for example, every time the crank position sensor 23 outputs a pulse signal).

  In the cold cooperative control routine, the ECU 27 first determines in S101 whether or not the value of the warm-up completion flag is “1”. The warm-up completion flag is a storage area set in advance in the RAM of the ECU 27. When the internal combustion engine 1 is in a cold state before the completion of warm-up, “0” is stored, and the internal combustion engine 1 enters a warm-up completion state. In some cases, “1” is stored.

  If it is determined in S101 that the value of the warm-up completion flag is “1”, the ECU 27 ends the execution of this routine.

If it is determined in S101 that the value of the warm-up completion flag is not “1”, the ECU 27 proceeds to S102. In S102, the ECU 27 outputs an output signal from the water temperature sensor 24 (hereinafter referred to as cooling water temperature: THW), an output signal from the accelerator position sensor 25 (hereinafter referred to as accelerator opening: ACCP), and an output signal value from the air flow meter 26. (Hereinafter referred to as intake air amount: Ga) and engine speed: NE are input.

  In S103, the ECU 27 determines whether or not the coolant temperature: THW input in S102 is lower than a warm-up determination temperature: T (for example, 50 ° C.).

  If it is determined in S103 that the coolant temperature: THW is not lower than the warm-up determination temperature: T, the ECU 27 changes the value of the warm-up completion flag to “1” in S108 and ends the execution of this routine. .

  If it is determined in S103 that the coolant temperature: THW is lower than the warm-up determination temperature: T, the ECU 27 proceeds to S104. In S104, the ECU 27 calculates a reference compression ratio: εt using the accelerator opening: ACCP and the engine speed: NE input in S102 as parameters.

  Reference compression ratio: εt corresponds to a target compression ratio when the internal combustion engine 1 is in a warm-up completion state. In the ROM of the ECU 27, a map showing the relationship between the engine speed NE when the internal combustion engine 1 is in the warm-up completion state, the accelerator opening degree: ACCP, and the reference compression ratio: εt is stored in advance. The engine speed of the internal combustion engine 1 is NE and the accelerator opening is a reference compression ratio suitable for ACCP: εt is uniquely determined.

  In S105, the ECU 27 calculates a target compression ratio: ε by adding a predetermined correction value: Δε to the reference compression ratio: εt. The correction value: Δε may be a fixed value, but may be a variable value that increases as the cooling water temperature decreases, as shown in FIG. 3.

  In S106, the ECU 27 calculates a target fuel injection amount: Qinj using the intake air amount: Ga input in S102 as a parameter.

  In S <b> 107, the ECU 27 calculates the fuel injection ratio between the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22. The fuel injection ratio is a ratio between the fuel amount injected from the fuel injection valve 21 in the intake passage and the fuel amount injected from the in-cylinder fuel injection valve 22 in the target fuel injection amount: Qinj. The fuel injection ratio of the in-passage fuel injection valve 21 is set to 100%, and the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 0%.

  The ECU 27 adds the fuel injection ratio (= 100%) of the fuel injection valve 21 in the intake passage to the target fuel injection amount: Qinj calculated in S106, and sets the target injection amount: Qintake of the fuel injection valve 21 in the intake passage. In addition to calculating the target fuel injection amount: Qinj, the fuel injection ratio (= 0%) of the in-cylinder fuel injection valve 22 is added to the target fuel injection amount: Qinj to calculate the target injection amount: Qcylinder.

  The ECU 27 once ends the execution of this routine when the execution of S107 is completed. Thereafter, the ECU 27 controls the drive mechanism 20 in accordance with the target compression ratio: ε, and controls the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22 in accordance with the target injection amounts Qintake and Qcycler.

  When the internal combustion engine 1 is in a cold state before the completion of warm-up, the drive mechanism 20, the intake passage fuel injection valve 21, and the target injection ratio: ε, the target injection amount Qtake, and the target injection amount: Qcylinder, When the in-cylinder fuel injection valve 22 is controlled, all of the target fuel injection amount: Qinj is injected from the intake passage fuel injection valve 21, and the compression ratio becomes higher than after the completion of warm-up.

  When all of the target fuel injection amount: Qinj is injected from the fuel injection valve 21 in the intake passage, the temperature in the combustion chamber 10 is less likely to decrease than when fuel is injected from the in-cylinder fuel injection valve 22. Become. This is because most of the fuel injected from the fuel injection valve 21 in the intake passage is vaporized by using the heat energy in the intake port 11 and the kinetic energy of the intake air, so that the fuel is consumed in the combustion chamber 10. This is thought to be due to a decrease in heat energy.

  Further, when the compression ratio becomes higher than after the completion of warm-up, the compression end temperature rises and the thermal energy in the combustion chamber 10 increases.

  Therefore, the temperature in the combustion chamber 10 is easily raised and hardly lowered, and it is possible to improve the thermal efficiency, reduce the discharge amount of unburned fuel components, and promote warm-up.

  In this embodiment, the coolant temperature: THW is used as a parameter for determining the warm-up state of the internal combustion engine 1. However, the lubricating oil temperature, the elapsed time (starting time) from the start, and the integration from the start You may make it discriminate | determine as parameters, such as the amount of intake air, the amount of fuel injections from the time of starting.

  Next, a second embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from that of the first embodiment will be described, and description of the same configuration will be omitted.

  In the first embodiment described above, cooperative control suitable for improving thermal efficiency, promoting warm-up, and reducing emissions when the internal combustion engine 1 is in a cold state (non-warm-up state) before the completion of warm-up has been described. In the present embodiment, cooperative control suitable for improving the thermal efficiency when the internal combustion engine 1 is in a high rotation / high load operation state will be described.

  When the internal combustion engine 1 is in a high rotation / high load operation state, the time required for one cycle is shortened and the target fuel injection amount Qinj is increased, so that it is necessary to mix fuel and intake air in a short time.

  Further, the fuel injected from the in-cylinder fuel injection valve 22 can spend less time for mixing the intake air than the fuel injected from the fuel injection valve 21 in the intake passage.

  When the internal combustion engine 1 is in a high speed / high load operation state, the fuel injection ratio of the fuel injection valve 21 in the intake passage is higher than the fuel injection ratio of the in-cylinder fuel injection valve 22 to solve the above problems. A possible method is to increase the time that can be spent in the intake air mixing.

  However, when the fuel injection ratio of the fuel injection valve 21 in the intake passage becomes high, a large amount of fuel injected from the fuel injection valve 21 in the intake passage hinders the flow of intake air in the intake port 11 and the intake charging efficiency decreases. there's a possibility that.

  In the cooperative control of this embodiment, when the internal combustion engine 1 is in a high rotation / high load operation state, the fuel injection ratio of the in-cylinder fuel injection valve 22 is higher than that in the intake passage fuel injection valve 21, and the same operation condition Below, the compression ratio is made higher than when the fuel injection ratio of the fuel injection valve 21 in the intake passage is 100%.

  Hereinafter, the cooperative control in the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a cooperative control routine at the time of high rotation and high load. The high rotation / high load cooperative control routine is a routine executed by the ECU 27 at predetermined time intervals.

  In the high rotation / high load cooperative control routine, the ECU 27 first outputs the output signal of the water temperature sensor 24 (cooling water temperature: THW), the output signal of the accelerator position sensor 25 (accelerator opening: ACCP), and the air flow meter 26 in S201. An output signal (intake air amount: Ga) and engine speed: NE are input.

  In S202, the ECU 27 determines whether or not the engine speed: NE input in S102 is higher than a predetermined speed: NEt. Predetermined rotational speed: NEt is a threshold value for determining whether or not the internal combustion engine 1 is in a high rotational operation state. This threshold varies depending on the type of internal combustion engine, but is about 4000 to 5000 revolutions.

  If it is determined in S202 that the engine speed NE is not higher than the predetermined engine speed NEt (the engine engine speed NE is equal to or less than the predetermined engine speed NEt), the ECU 27 ends the execution of this routine.

  When it is determined in S202 that the engine speed NE is higher than the predetermined engine speed NEt, the ECU 27 proceeds to S203 and determines whether or not the internal combustion engine 1 is in the high load operation region. In this embodiment, accelerator opening: ACCP is used as a parameter representing the load of the internal combustion engine 1. That is, the ECU 27 determines whether or not the accelerator opening: ACCP inputted in S201 is larger than the predetermined opening: ACCPt.

  If it is determined in S203 that the accelerator opening: ACCP is not larger than the predetermined opening: ACCPt (accelerator opening: ACCP is not more than the predetermined opening: ACCPt), the ECU 27 ends the execution of this routine.

If it is determined in S203 that the accelerator opening: ACCP is larger than the predetermined opening: ACCPt, the ECU 27 calculates a target fuel injection amount: Qinj using the intake air amount: Ga input in S201 as a parameter in S204. To do.

  In S205, the ECU 27 calculates a fuel injection ratio between the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22. In this embodiment, the fuel injection ratio of the fuel injection valve 21 in the intake passage is 0%, and the fuel injection ratio of the in-cylinder fuel injection valve 22 is 100%.

  The ECU 27 adds the fuel injection ratio (= 0%) of the fuel injection valve 21 in the intake passage to the target fuel injection amount: Qinj calculated in S204 and sets the target injection amount: Qintake of the fuel injection valve 21 in the intake passage. While calculating, the fuel injection ratio (= 100%) of the in-cylinder fuel injection valve 22 is added to the target fuel injection amount: Qinj to calculate the target injection amount: Qcylinder of the in-cylinder fuel injection valve 22.

  In S206, the ECU 27 calculates a target compression ratio: ε using the accelerator opening: ACCP and the engine speed: NE input in S201 as parameters.

  FIG. 5 is a diagram showing the relationship between the load (accelerator opening: ACCP), engine speed: NE, and target compression ratio. 5 indicates the target compression ratio when the fuel injection ratio of the fuel injection valve 21 in the intake passage is 100%, and the solid line in FIG. 5 indicates that the fuel injection ratio of the in-cylinder fuel injection valve 22 is 100%. Shows the target compression ratio. Further, εmin in FIG. 5 represents the lowest compression ratio that can be realized by the variable compression ratio mechanism of the present embodiment, and εmax represents the highest compression ratio.

When the fuel injection ratio of the fuel injection valve 21 in the intake passage is set to 100% during high speed / high load operation, most of the injected fuel is vaporized using the heat energy in the intake port 11 and the kinetic energy of the intake air. Therefore, the thermal energy consumed for vaporizing fuel in the combustion chamber 10 is reduced. When the thermal energy consumed for fuel vaporization in the combustion chamber 10 decreases, the temperature in the combustion chamber 10 is unlikely to decrease and knocking is likely to occur.

  Therefore, when the fuel injection ratio of the fuel injection valve 21 in the intake passage is set to 100%, it is necessary to reduce the target compression ratio.

  On the other hand, when the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100% during high rotation / high load operation, the combustion chamber 10 consumes heat energy in the combustion chamber 10 when the injected fuel is vaporized. The temperature inside tends to decrease.

  Therefore, when the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100% during high speed / high load operation, the target is higher than when the fuel injection ratio of the fuel injection valve 21 in the intake passage is set to 100%. It is possible to increase the compression ratio.

  Here, returning to FIG. 4, the ECU 27 calculates the target compression ratio: ε based on the map as shown in FIG. 5 described above in S206, and ends the execution of this routine. Thereafter, the ECU 27 controls the drive mechanism 20 in accordance with the target compression ratio: ε, and controls the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22 in accordance with the target injection amounts Qintake and Qcycler.

  When the drive mechanism 20, the intake manifold fuel injection valve 21, and the in-cylinder fuel injection valve 22 are controlled in accordance with the target compression ratio: ε, the target injection amount Qintake, and the target injection amount: Qcylinder, the target fuel injection amount: All of Qinj is injected from the in-cylinder fuel injection valve 22, and the compression ratio is higher than when all of the target fuel injection amount: Qinj is injected from the fuel injection valve 21 in the intake passage.

  In this case, a decrease in intake charging efficiency is suppressed, and the thermal efficiency of the internal combustion engine 1 is improved. Furthermore, since the injection ratio from the in-cylinder fuel injection valve 22 can be vaporized in a short time by increasing the compression ratio, a suitable combustible air-fuel mixture can be formed.

  Therefore, according to the present embodiment, it is possible to realize the suppression of the reduction in intake charge efficiency, the improvement of the thermal efficiency, the suppression of knocking, and the formation of a good combustible mixture.

  The target fuel injection amount: Qinj increases and the in-cylinder temperature tends to decrease as the load on the internal combustion engine 1 increases. Therefore, the compression ratio may increase as the load increases.

  In-cylinder fuel injection valve 22 must inject the target fuel injection amount in a shorter time as the engine speed increases. That is, the amount of fuel that the in-cylinder fuel injection valve 22 should inject per unit time (hereinafter referred to as the required fuel amount per unit time) increases as the engine speed increases. For this reason, when the required injection amount per unit time exceeds the maximum injection amount of the in-cylinder fuel injection valve 22, a part of the target fuel injection amount: Qinj is injected from the intake passage fuel injection valve 21. It may be.

  Since the inertia force of the intake air is large during high speed / high load operation, if the fuel injection amount of the fuel injection valve 21 in the intake passage is small, it is difficult to block the flow of intake air in the intake port 11 and the intake charging efficiency is reduced. Is suppressed.

  Next, a third embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from the above-described second embodiment will be described, and description of the same configuration will be omitted.

  In the above-described second embodiment, the compression ratio is increased at the time of high rotation and high load, and the fuel injection ratio of the in-cylinder fuel injection valve 22 is increased to improve the charging efficiency of intake air, improve the thermal efficiency of the internal combustion engine 1, suppress knocking, and improve An example of forming a combustible mixture was described. On the other hand, in this embodiment, an example of improving thermal efficiency and fuel consumption at low rotation and high load will be described.

FIG. 6 is a diagram showing a schematic configuration of a drive train to which the present invention is applied. As shown in FIG. 6, the configuration of the internal combustion engine 1 is the same as that of the first embodiment. The internal combustion engine 1 is connected to an automatic transmission 28 that continuously changes the gear ratio continuously and continuously.

  A vehicle speed sensor 29 is attached to the automatic transmission 28. The automatic transmission 28 and the vehicle speed sensor 29 are electrically connected to an electronic control unit (T-ECU) 30 for controlling the gear ratio of the automatic transmission 28.

  The T-ECU 30 controls the gear ratio of the automatic transmission 28 and the operating state of the internal combustion engine 1 while performing bidirectional communication with the ECU 27. For example, the T-ECU 30 uses the output signal (vehicle speed: V) of the vehicle speed sensor 29 and the output signal (accelerator opening: ACCP) of the accelerator position sensor 25 as parameters, and the operating state of the internal combustion engine 1. To control.

  Specifically, the T-ECU 30 calculates a target engine speed (input speed of the automatic transmission 28) of the internal combustion engine 1 using the accelerator opening: ACCP as a parameter, and the target engine speed and vehicle speed: V The transmission ratio of the automatic transmission 28 is determined based on the difference.

  When calculating the target engine speed of the internal combustion engine 1, the T-ECU 30 calculates the target engine speed according to the operation diagram of the internal combustion engine 1 as shown in FIG. A solid line in FIG. 7 indicates an operation line of the internal combustion engine 1, a dotted line indicates an iso-fuel consumption line of the internal combustion engine 1, and an alternate long and short dash line indicates an iso-output line of the internal combustion engine 1.

  The operation line of the internal combustion engine 1 is determined so as to pass through the intersection having the lowest fuel consumption and the highest thermal efficiency among the intersections of the equal output line and the equal fuel consumption line. According to such an operation line, the target engine speed excellent in fuel efficiency and thermal efficiency can be uniquely determined using the accelerator opening degree: ACCP as a parameter.

  Incidentally, as is apparent from the operation line of FIG. 7, it is difficult to say that the fuel consumption is optimal when the internal combustion engine 1 is in the low rotation / high load operation state. Since the low-rotation / high-load driving region in the vehicle traveling process is relatively frequently used, the improvement of fuel consumption in this driving region is effective.

  In addition, in an internal combustion engine equipped with a variable compression ratio mechanism, the compression ratio is lowered as the load increases. Therefore, the compression ratio is lowered in the low rotation / high load operation region, and the thermal efficiency is lowered. In particular, when the fuel injection ratio of the fuel injection valve 21 in the intake passage is set to 100%, the compression ratio needs to be greatly reduced, and the thermal efficiency is significantly reduced.

  Therefore, in this embodiment, when the internal combustion engine is in the low rotation / high load operation state, the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100%, and the fuel injection valve 21 in the intake passage under the same operation conditions. The compression ratio was made higher than when the fuel injection ratio was 100%.

However, if the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100% when the internal combustion engine 1 is in a cold state before the warm-up is completed, fuel vaporization is insufficient and a combustible mixture is formed. Therefore, it is assumed that the above control is performed only at the time of low rotation / high load operation after completion of warm-up.

  Hereinafter, cooperative control in the present embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing a cooperative control routine at the time of low rotation and high load. This low-rotation / high-load cooperative control routine is a routine that the ECU 27 executes every predetermined time.

  In the low rotation / high load cooperative control routine, the ECU 27 first outputs an output signal of the water temperature sensor 24 (cooling water temperature: THW), an output signal of the accelerator position sensor 25 (accelerator opening: ACCP), and the air flow meter 26 in S301. An output signal (intake air amount: Ga) and engine speed: NE are input.

  In S302, the ECU 27 determines whether or not the coolant temperature: THW input in S301 is equal to or higher than the warm-up determination temperature: T.

  If it is determined in S302 that the coolant temperature: THW is lower than the warm-up determination temperature: T, the ECU 27 ends the execution of this routine.

  If it is determined in S302 that the coolant temperature: THW is equal to or higher than the warm-up determination temperature: T, the ECU 27 proceeds to S303. In S303, the ECU 27 determines whether or not the engine speed: NE input in S301 is lower than a predetermined speed: NEl. The predetermined rotation speed: NEl is a threshold value for determining whether or not the internal combustion engine 1 is in a low rotation operation state. This threshold varies depending on the type of internal combustion engine, but is about 2000 to 3000 revolutions.

  When it is determined in S303 that the engine speed NE is not lower than the predetermined engine speed NE1 (the engine engine speed NE is equal to or greater than the predetermined engine speed NE1), the ECU 27 ends the execution of this routine.

  If it is determined in S303 that the engine speed NE is lower than the predetermined engine speed NE1, the ECU 27 proceeds to S304, whether or not the internal combustion engine 1 is in the high load operation region, that is, the accelerator input in S301. It is determined whether the opening: ACCP is larger than the predetermined opening: ACCPt.

  If it is determined in S304 that the accelerator opening: ACCP is not larger than the predetermined opening: ACCPt (accelerator opening: ACCP is not larger than the predetermined opening: ACCPt), the ECU 27 ends the execution of this routine.

  If it is determined in S304 that the accelerator opening: ACCP is larger than the predetermined opening: ACCPt, the ECU 27 proceeds to S305. In S305, the ECU 27 calculates a target fuel injection amount: Qinj using the intake air amount: Ga input in S301 as a parameter.

  In S306, the ECU 27 calculates the fuel injection ratio between the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22. In this embodiment, the fuel injection ratio of the fuel injection valve 21 in the intake passage is 0%, and the fuel injection ratio of the in-cylinder fuel injection valve 22 is 100%.

The ECU 27 adds the fuel injection ratio (= 0%) of the fuel injection valve 21 in the intake passage to the target fuel injection amount: Qinj calculated in S305, and sets the target injection amount: Qintake of the fuel injection valve 21 in the intake passage. While calculating, the fuel injection ratio (= 100%) of the in-cylinder fuel injection valve 22 is added to the target fuel injection amount: Qinj, and the target injection amount: Qcy of the in-cylinder fuel injection valve 22
Linder is calculated.

  In S307, the ECU 27 calculates the target compression ratio: ε using the accelerator opening: ACCP and the engine speed: NE input in S301 as parameters.

  FIG. 9 is a diagram showing the relationship between the accelerator opening: ACCP, the engine speed: NE, and the target compression ratio. In FIG. 9, the solid line indicates the target compression ratio when the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100%, and the dotted line indicates that when the fuel injection ratio of the fuel injection valve 21 in the intake passage is set to 100%. The target compression ratio is shown.

  The target compression ratio at the time of low rotation and high load is the value when the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100% than when the fuel injection ratio of the fuel injection valve 21 in the intake passage is set to 100%. Has been raised. This is because when the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100%, the temperature in the combustion chamber 10 is more likely to decrease than when the fuel injection ratio of the fuel injection valve 21 in the intake passage is set to 100%. This is because knocking hardly occurs.

  Returning to FIG. 8, the ECU 27 calculates the target compression ratio: ε in S307 according to the map shown in FIG. 9 described above, and ends the execution of this routine. Thereafter, the ECU 27 controls the drive mechanism 20 in accordance with the target compression ratio: ε, and controls the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22 in accordance with the target injection amounts Qintake and Qcycler.

  When the drive mechanism 20, the intake manifold fuel injection valve 21, and the in-cylinder fuel injection valve 22 are controlled in accordance with the target compression ratio: ε, the target injection amount Qintake, and the target injection amount: Qcylinder, the target fuel injection amount: All of Qinj is injected from the in-cylinder fuel injection valve 22, and the compression ratio is higher than when all of the target fuel injection amount: Qinj is injected from the fuel injection valve 21 in the intake passage. In this case, the thermal efficiency of the internal combustion engine 1 is improved, and the fuel efficiency is improved accordingly.

  Therefore, according to the present embodiment, it is possible to improve the thermal efficiency and the fuel consumption in the low rotation / high load operation region.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. Here, the configuration different from the above-described first embodiment will be described, and the description of the same configuration will be omitted.

  In the first embodiment described above, cooperative control suitable for improving thermal efficiency, promoting warm-up, and reducing emissions when the internal combustion engine 1 is in a cold state (non-warm-up state) before the completion of warm-up has been described. In this embodiment, cooperative control suitable for improving thermal efficiency and suppressing knocking when the internal combustion engine is in a low-load operation state after completion of warm-up will be described.

  FIG. 10 shows a schematic configuration of the internal combustion engine 1 in the present embodiment. The internal combustion engine 1 in this embodiment includes a variable valve mechanism 160 that changes the opening / closing timing of the intake valve 15, and the variable valve mechanism 160 is controlled by the ECU 27.

  For example, the ECU 27 controls the variable valve mechanism 160 so as to retard the opening timing of the intake valve 15 from the top dead center of the intake stroke when the internal combustion engine 1 is in a low load operation state.

If the valve opening timing of the intake valve 15 is retarded from the top dead center of the intake stroke during low load operation of the internal combustion engine 1, the flow velocity when the intake air flows into the combustion chamber 10 increases, improving the charging efficiency and improving the combustion. Can be achieved.

  By the way, the control of the variable valve mechanism 160 as described above is effective when the internal combustion engine 1 is in a cold state before the warm-up is completed, but may cause knocking after the warm-up of the internal combustion engine 1 is completed. .

  That is, if the above control is performed before the warm-up of the internal combustion engine 1 is completed, the kinetic energy of the intake air is converted into thermal energy in the combustion chamber 10, and the temperature in the combustion chamber 10 rises to promote fuel vaporization. If the above control is performed after the warm-up of the internal combustion engine 1 is completed, there is a possibility that the temperature in the combustion chamber 10 will rise excessively and induce knocking. In particular, in an internal combustion engine equipped with a variable compression ratio mechanism, the compression ratio increases as the load decreases. Therefore, knocking is likely to occur when the above control is performed during low load operation.

  Therefore, in this embodiment, when the internal combustion engine 1 is in the low load operation state after the warm-up is completed, the opening timing of the intake valve 15 is set before the intake stroke top dead center under the same operation conditions. The compression ratio is lowered and the fuel injection ratio of the in-cylinder fuel injection valve is increased.

  Hereinafter, cooperative control in the present embodiment will be described with reference to FIG. FIG. 11 is a flowchart showing a low load cooperative control routine. This low load cooperative control routine is a routine executed by the ECU 27 at predetermined time intervals.

  In the low load cooperative control routine, the ECU 27 first determines in S401 whether or not the value of the warm-up completion flag is “1”.

  If it is determined in S401 that the value of the warm-up completion flag is “1”, the ECU 27 ends the execution of this routine.

  If it is determined in S401 that the value of the warm-up completion flag is not “1”, the ECU 27 proceeds to S402. In S402, the ECU 27 outputs an output signal from the water temperature sensor 24 (cooling water temperature: THW), an output signal from the accelerator position sensor 25 (accelerator opening: ACCP), an output signal from the air flow meter 26 (intake air amount: Ga), engine Rotational speed: NE and intake valve 15 opening timing: IVO are input.

  In S403, the ECU 27 determines whether or not the coolant temperature THW input in S402 is lower than the warm-up determination temperature T.

  If it is determined in S403 that the coolant temperature: THW is equal to or higher than the warm-up determination temperature: T, the ECU 27 changes the value of the warm-up completion flag to “1” in S409 and ends the execution of this routine. .

  If it is determined in S403 that the coolant temperature: THW is less than the warm-up determination temperature: T, the ECU 27 proceeds to S404. In S404, the ECU 27 determines whether or not the opening timing: IVO of the intake valve 15 input in S402 is after the intake stroke top dead center.

  If it is determined in S404 that the opening timing of the intake valve 15: IVO is not after the intake stroke top dead center (that is, the valve opening timing: IVO is before the intake stroke top dead center), the ECU 27 Ends routine execution.

If it is determined in S404 that the opening timing of the intake valve 15: IVO is after the top dead center of the intake stroke, the ECU 27 proceeds to S405. In S405, the ECU 27 performs S
The reference compression ratio: εt is calculated using the accelerator opening: ACCP and the engine speed: NE input in 402 as parameters.

  The reference compression ratio εt corresponds to a target compression ratio when the opening timing IVO of the intake valve 15 is set before the intake stroke top dead center. In the ROM of the ECU 27, the relationship between the opening speed of the intake valve 15: IVO and the engine speed: NE and the accelerator opening: ACCP and the reference compression ratio: εt when the IVO is set before the top dead center of the intake stroke. It is assumed that the map shown is stored in advance.

  In S406, the ECU 27 calculates a target compression ratio: ε by subtracting a predetermined correction value: Δε from the reference compression ratio: εt. The correction value: Δε may be a fixed value, but may be a variable value that increases as the cooling water temperature increases as shown in FIG.

  In S407, the ECU 27 calculates a target fuel injection amount: Qinj using the intake air amount: Ga input in S402 as a parameter.

  In step S408, the ECU 27 calculates the fuel injection ratio between the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22. In this embodiment, the fuel injection ratio of the fuel injection valve 21 in the intake passage is set to 0% and the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100%.

  The ECU 27 adds the fuel injection ratio (= 0%) of the fuel injection valve 21 in the intake passage to the target fuel injection amount: Qinj calculated in S407 and calculates the target injection amount of the fuel injection valve 21 in the intake passage: Qintake ( = 0) and the target fuel injection amount: Qinj is calculated by adding the fuel injection ratio (= 100%) of the in-cylinder fuel injection valve 22 to the target fuel injection amount: Qinj. ) Is calculated.

  The ECU 27 once ends the execution of this routine when the execution of S408 is completed. Thereafter, the ECU 27 controls the drive mechanism 20 in accordance with the target compression ratio: ε, and controls the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22 in accordance with the target injection amounts Qintake and Qcycler.

  When the internal combustion engine 1 is in a low load operation state after completion of warm-up and the valve opening timing of the intake valve 15: IVO is set after the top dead center of the intake stroke, the aforementioned target compression ratio: ε, the target injection amount Qtake When the drive mechanism 20, the intake passage fuel injection valve 21, and the in-cylinder fuel injection valve 22 are controlled according to the target injection amount: Qcyclinder, the opening timing of the intake valve 15: IVO is the intake stroke under the same operating conditions. The compression ratio is lowered and the temperature in the combustion chamber 10 is lowered as compared with a case where fuel is injected from the fuel injection valve 21 in the intake passage and set before the top dead center.

  As a result, the occurrence of knocking is suppressed even if the intake kinetic energy is increased by setting the valve opening time: IVO of the intake valve 15 after the top dead center of the intake stroke. Further, when the knocking is suppressed by using both the decrease in the compression ratio and the increase in the fuel injection ratio of the in-cylinder fuel injection valve 22 as in this embodiment, the compression ratio is lower than that in the case where the knocking is suppressed only by the decrease in the compression ratio. The amount of decrease can be reduced, and a decrease in thermal efficiency due to a decrease in compression ratio can be suppressed.

  Further, according to the above-described cooperative control, knocking can be suppressed without advancing the valve opening timing: IVO of the intake valve 15, so that the charging efficiency of intake air is not reduced.

Since the temperature in the combustion chamber 10 can be lowered to some extent by increasing the fuel injection ratio of the in-cylinder fuel injection valve 22, the fuel injection ratio of the in-cylinder fuel injection valve 22 is increased without reducing the compression ratio. You may do it. In this case, the occurrence of knocking can be suppressed while maintaining the effect of improving the thermal efficiency by the variable compression ratio mechanism.

  Further, when the internal combustion engine 1 includes a knock sensor, the fuel injection ratio of the in-cylinder fuel injection valve 22 may be first increased, and then the compression ratio may be decreased if a knock is detected. . In this case, since the compression ratio is reduced only when the occurrence of knocking cannot be suppressed due to the increase in the fuel injection ratio of the in-cylinder fuel injection valve 22, the reduction in thermal efficiency can be minimized.

  Next, a fifth embodiment of the present invention will be described with reference to FIGS. Here, the configuration different from the above-described first embodiment will be described, and the description of the same configuration will be omitted.

  In the first embodiment described above, cooperative control suitable for improving thermal efficiency, promoting warm-up, and reducing emissions when the internal combustion engine 1 is in a cold state (non-warm-up state) before the warm-up is completed has been described. In this embodiment, cooperative control suitable for improving thermal efficiency and suppressing knocking at the time of high load of an internal combustion engine equipped with a supercharger will be described.

  FIG. 13 shows a schematic configuration of the internal combustion engine 1 in the present embodiment. The intake pipe 13 of the internal combustion engine 1 in this embodiment is provided with a supercharger 31 that compresses intake air. A supercharging pressure sensor (intake pressure sensor) 32 for detecting a supercharging pressure is provided downstream of the supercharger 31 in the intake pipe 13.

  The supercharger 31 may be a mechanical supercharger that uses the power of the internal combustion engine 1, or may be a centrifugal supercharger that uses the exhaust energy of the internal combustion engine 1.

  When the internal combustion engine 1 provided with the supercharger 31 is in a high load operation state, the in-cylinder pressure increases as the supercharging pressure increases, and therefore knocking is likely to occur. In order to suppress the occurrence of such knocking only by compression ratio control, it is necessary to greatly reduce the compression ratio. However, when the compression ratio is significantly reduced, the thermal efficiency of the internal combustion engine is reduced, and deterioration of fuel consumption is induced.

  Therefore, in this embodiment, when the internal combustion engine 1 is in a high load operation state, the fuel injection ratio of the in-cylinder fuel injection valve 22 is increased in addition to the decrease in the compression ratio.

  Hereinafter, cooperative control in the present embodiment will be described with reference to FIG. FIG. 13 is a flowchart showing a high load cooperative control routine. This low load cooperative control routine is a routine executed by the ECU 27 at predetermined time intervals.

  In the high load cooperative control routine, first in step S501, the ECU 27 outputs an output signal from the accelerator position sensor 25 (accelerator opening: ACCP), an output signal from the air flow meter 26 (intake air amount: Ga), an engine speed: NE, and An output signal of the supercharging pressure sensor 32 (hereinafter referred to as supercharging pressure: Pb) is input.

  In S502, the ECU 27 determines whether or not the internal combustion engine 1 is in a high load operation state using the accelerator opening: ACCP input in S501 as a parameter. Specifically, the ECU 27 determines whether or not the accelerator opening: ACCP is larger than a predetermined opening: ACCPt.

If it is determined in S502 that the accelerator opening: ACCP is not greater than the predetermined opening: ACCPt (accelerator opening: ACCP ≦ predetermined opening: ACCPt), the ECU 27 ends the execution of this routine.

  If it is determined in S502 that the accelerator opening: ACCP is larger than the predetermined opening: ACCPt, the ECU 27 proceeds to S503. In S503, the ECU 27 calculates a target fuel injection amount: Qinj using the intake air amount: Ga input in S501 as a parameter.

  In S504, the ECU 27 calculates the fuel injection ratio between the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22. In this embodiment, the fuel injection ratio of the fuel injection valve 21 in the intake passage is 0%, and the fuel injection ratio of the in-cylinder fuel injection valve 22 is 100%.

  The ECU 27 adds the fuel injection ratio (= 0%) of the fuel injection valve 21 in the intake passage to the target fuel injection amount: Qinj calculated in S503, and obtains the target injection amount: Qintake of the fuel injection valve 21 in the intake passage. While calculating, the fuel injection ratio (= 100%) of the in-cylinder fuel injection valve 22 is added to the target fuel injection amount: Qinj to calculate the target injection amount: Qcylinder of the in-cylinder fuel injection valve 22.

  In S505, the ECU 27 calculates the reference compression ratio: εt using the accelerator opening: ACCP and the engine speed: NE input in S501 as parameters. The reference compression ratio: εt corresponds to a target compression ratio when supercharging by the supercharger 31 is not performed.

  In S506, the ECU 27 calculates a target compression ratio: ε by subtracting a predetermined value: Δε from the reference compression ratio: εt calculated in S505. Here, the predetermined value: [Delta] [epsilon] has a larger value as the supercharging pressure Pb becomes higher as shown in FIG.

  When the ECU 27 finishes executing the process of S506, the ECU 27 ends the execution of this routine. Thereafter, the ECU 27 controls the drive mechanism 20 in accordance with the target compression ratio: ε, and controls the intake passage fuel injection valve 21 and the in-cylinder fuel injection valve 22 in accordance with the target injection amounts: Qintake and Qcylinder.

  When the drive mechanism 20, the intake passage fuel injection valve 21, and the in-cylinder fuel injection valve 22 are controlled in accordance with the target compression ratio: ε, the target injection amount Qintake, and the target injection amount: Qcylinder, the target fuel injection amount: All of Qinj is injected from the in-cylinder fuel injection valve 22, and the compression ratio is lower than when the supercharger 31 is not supercharged.

  When the fuel injection ratio of the in-cylinder fuel injection valve 22 is set to 100% and the compression ratio is decreased, the temperature in the combustion chamber 10 is likely to decrease, and the occurrence of knocking is suppressed. At that time, since the reduction in the compression ratio and the increase in the fuel injection ratio of the in-cylinder fuel injection valve 22 are used together to suppress knocking, the amount of reduction in the compression ratio is less than that in the case where knocking is suppressed only by reducing the compression ratio It is possible to suppress a decrease in thermal efficiency due to a decrease in compression ratio.

  Therefore, according to the present embodiment, the occurrence of knocking can be suppressed while minimizing the decrease in thermal efficiency.

  In this embodiment, the accelerator opening: ACCP is used as a parameter for determining whether or not the internal combustion engine 1 is in a high load operation state. However, the accelerator opening: ACCP is used instead of the accelerator opening: ACCP. Also good.

The figure which shows schematic structure of the internal combustion engine in Example 1. FIG. The figure which shows the cold time cooperative control routine in Example 1 Diagram showing the relationship between cooling water temperature and correction value The figure which shows the cooperation control routine at the time of high rotation and high load in Example 2 The figure which shows the relationship between the load in Example 2, an engine speed, and a target compression ratio. The figure which shows schematic structure of the drive train in Example 3. The figure which shows the operating line of the internal combustion engine in Example 3. The figure which shows the low speed and the high load cooperative control routine in Example 3. The figure which shows the relationship between the load in Example 3, an engine speed, and a target compression ratio. The figure which shows schematic structure of the internal combustion engine in Example 4. FIG. The figure which shows the low load cooperation control routine in Example 4. The figure which shows the relationship between the cooling water temperature in Example 4, and a correction value. The figure which shows schematic structure of the internal combustion engine in Example 5. FIG. The figure which shows the high load time cooperative control routine in Example 5. The figure which shows the relationship between the supercharging pressure in Example 5, and a correction value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 7 ... Cylinder 10 ... Combustion chamber 11 ... Intake port 12 ... Exhaust port 13 ... Intake pipe 14 ... Exhaust pipe 15 ... Intake valve 20 ... Drive mechanism 21 ... Injection passage fuel injection valve 22 ... In-cylinder fuel injection valve 23 ... Crank position sensor 24 ... Water temperature sensor 25 ... Accelerator position sensor 26 ... Air flow meter 28 ... Automatic transmission 30 ... T-ECU
31 ... Supercharger 32 ... Supercharging pressure sensor

Claims (6)

An in-cylinder fuel injection valve for injecting fuel into the cylinder;
An intake passage fuel injection valve for injecting fuel into the intake passage;
A variable compression ratio mechanism for changing the compression ratio of the internal combustion engine;
Detecting means for detecting a parameter relating to the engine operating state;
Control means for controlling the variable compression ratio mechanism and controlling the fuel injection ratio of the in-cylinder fuel injection valve and the fuel injection valve in the intake passage based on the parameters;
A control device for an internal combustion engine, comprising: The parameter is a parameter related to a warm-up state of the internal combustion engine,
When the control means determines that the internal combustion engine is in a non-warm-up state based on the parameters, the control means controls the variable compression ratio mechanism to increase the compression ratio and increases the fuel injection ratio of the fuel injection valve in the intake passage. The control apparatus for an internal combustion engine according to claim 1. The parameters are parameters related to the rotational speed and load of the internal combustion engine,
The control means increases the compression ratio and increases the fuel injection ratio of the in-cylinder fuel injection valve when it is determined that the internal combustion engine is in a high rotation / high load operation state based on the parameter. The control apparatus for an internal combustion engine according to claim 1. A variable valve mechanism for increasing the kinetic energy of the intake air by changing the valve opening characteristics of the intake valve at a low load of the internal combustion engine;
The parameters are parameters related to the warm-up state and load of the internal combustion engine,
When it is determined that the internal combustion engine is in a warm-up state and in a low-load operation state based on the parameters, the control means controls the variable compression ratio mechanism to lower the compression ratio and controls the in-cylinder fuel injection valve. 2. The control device for an internal combustion engine according to claim 1, wherein the fuel injection ratio is increased. A supercharger for compressing intake air of the internal combustion engine;
The parameter is a parameter related to the load of the internal combustion engine,
When the control means determines that the internal combustion engine is in a high load operation state based on the parameter, the control means controls the variable compression ratio mechanism to lower the compression ratio and increases the fuel injection ratio of the in-cylinder fuel injection valve. The control device for an internal combustion engine according to claim 1. The parameters are parameters related to the rotational speed, load, and warm-up state of the internal combustion engine,
When the control means determines that the internal combustion engine is in a low rotation / high load operation state after the warm-up is completed based on the parameters, the control means controls the variable compression ratio mechanism to increase the compression ratio and the in-cylinder fuel injection valve 2. The control device for an internal combustion engine according to claim 1, wherein the fuel injection ratio of the engine is increased.

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